A: The categories that offer the most potential for advertisers are naturally those where the searcher has the greatest interest in making a purchase or conducting research prior to making a purchase. Shopping and travel are two obvious examples.

That being said, for any search category volume is going to be critical. Managing an advertising campaign has an incompressible fixed cost, so advertisers are only going to go where there’s enough volume to produce a positive return on their efforts. Irrespective of the degree to which the search experience is compelling, or the searchers motivated to purchase, this is often a very big challenge for anyone starting a new search engine.

Developing the technology will of course depend on the nature of the new technology. Visual front-ends, for example, can be produced rather cheaply. taggalaxy.de is impressive and was built by a single individual. While I don’t have the details, RedZ, which has a SearchMe-like interface, is probably another good example. Search engines that require algorithmic work, especially if scale is required for network effects or optimization, will be faced with a considerably more expensive task.

Mark Cramer is CEO of Surf Canyon, a company that makes a free browser add-on for real-time personalized search. Mark explains how his add-on has come to be downloaded over 1.3 million times and how it came to be written up by Walt Mossberg. Mark also talks about add-on monetization and tells us how his company decided to make an add-on in the first place.